JPH10242209A - Apparatus and method of mounting conductive balls - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method of mounting fine conductive balls which is capable of simply detecting the balls remaining fixed to the lower face of a vacuum head due to wrong mounting procedure, after mounting the balls vacuumed to vacuum holes of the head on a work. SOLUTION: A light irradiator 21 at the side of a moving path of a vacuum head 12 irradiates with a light beam L along the bottom face of the head 12. A conductive ball 1 having a glossy spherical mirror surface reflects the beam L downwards. The reflected light d is incident on an optical fiber 29, reflected further by a mirror 25 to a light receiving part 26. This accurately detects the presence or absence of the ball 1 remaining fixed to the bottom face of the head 12 due to mounting failure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive ball mounting apparatus and method for mounting a conductive ball on a work.

[0002]

2. Description of the Related Art A flip chip or a BGA (Ball G
2. Description of the Related Art As a method for manufacturing an electronic component with a bump such as a lid array, a method using a conductive ball such as a solder ball is known. As a method for mounting conductive balls on a work such as a chip or a substrate, a method using a suction head is known.

In this method, conductive balls stored in a container or the like are vacuum-adsorbed and picked up in a large number of suction holes formed on the lower surface of a suction head, and the suction head is moved above a workpiece to move the suction balls. Since the conductive balls are mounted on the pads of the work, a large number of conductive balls can be collectively mounted on the work, so that there is an advantage that workability is good.

However, the method of mounting a conductive ball on a work using a suction head has a problem that a pickup error or a mounting error is likely to occur. Therefore, the present applicant has previously proposed a method for detecting a pickup error or a mounting error (Japanese Patent Application Laid-Open No. 8-97218). In this method, as shown in FIGS. 2 and 3 of the publication, a pickup error is detected by leaking light from a suction hole of a suction head (pickup head). In addition, FIG.
As shown in the figure, a light-emitting element and a light-receiving element are provided so as to sandwich the moving path of the suction head, and suction is performed depending on whether or not the light-receiving element receives light irradiated from the light-emitting element along the lower surface of the suction head. The presence or absence of a conductive ball on the lower surface of the head is detected. If the conductive ball is detected, it is determined that a mounting error has occurred.

[0005]

However, according to the above-mentioned conventional method, when the size of the conductive ball is small, the beam diameter of the light emitted from the light emitting element cannot be stopped down, so that the conductive ball cannot completely block the light. Therefore, there is a problem that the presence or absence of the conductive ball cannot be accurately determined.

When the size of the suction head increases,
The problem is that the distance between the light emitting element and the light receiving element increases, and the light emitted from the light emitting element diffuses, so that the conductive ball cannot completely block the light, and it is impossible to accurately determine the presence or absence of the conductive ball. There was a point. In order to solve this problem, it is conceivable to use a laser beam with a large power. However, a laser beam with a large power not only increases the equipment cost but also requires a new safety measure. Problems arise.

Accordingly, an object of the present invention is to provide a conductive ball mounting apparatus and a mounting method capable of easily and surely detecting minute conductive balls adhered to the lower surface of a suction head due to a mounting error.

[0008]

According to the present invention, there is provided an apparatus for mounting a conductive ball, comprising: a supply section for a conductive ball; a suction head having a plurality of suction holes for the conductive ball formed on a lower surface; A moving table for moving the suction head between a conductive ball supply unit and a work positioning unit;
A light irradiator that irradiates light along the lower surface of the suction head from the side of the suction head in the movement path of the suction head, and a spherical mirror surface of the conductive ball that is suctioned into the suction hole below the suction head. And a light receiving unit for receiving the light reflected downward.

[0009] The method of mounting a conductive ball according to the present invention comprises:
A step of picking up and picking up the conductive balls provided in the supply section of the conductive balls by the suction head in a plurality of suction holes on a lower surface thereof, and moving the suction head to a position above the work positioned at the positioning section. A step of mounting the conductive ball on the work, and after performing the mounting, irradiates light along a lower surface of the suction head from a light irradiator on a side of the suction head, and a light receiving unit provided below the suction head is provided. Determining the presence or absence of the conductive ball based on whether or not the reflected light is received.

[0010]

According to the present invention, since the surface of the conductive ball is a glossy spherical mirror surface such as a solder ball, the surface of the conductive ball is irradiated from the light irradiator along the lower surface of the suction head. The reflected light is reflected downward by the spherical mirror surface of the conductive ball, so that the reflected light can be reliably detected by the lower light receiving portion, and the presence or absence of the conductive ball can be accurately determined.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a conductive ball mounting apparatus according to an embodiment of the present invention, and FIGS. 2 and 3 are side views of the suction head and an optical system.

First, the overall structure of the conductive ball mounting device will be described with reference to FIG. Reference numeral 1 denotes a conductive ball, which is stored in a large amount in a supply unit 2 formed of a container. 3
Is a support for the supply unit.

A positioning section 5 for positioning the work 4 is provided on a side of the supply section 2. The positioning part 5 is X
The table 6, the Y table 7, and the work holder 8 are stacked, and the work 4 is held by the work holder 8. When the X-axis motor 9 and the Y-axis motor 10 are driven, the work 4 moves horizontally in the X direction and the Y direction, and its position is adjusted.

Reference numeral 12 denotes a suction head, on the lower surface of which are formed a number of suction holes 13 for vacuum-sucking the conductive balls 1 (see also FIG. 2). The suction head 12 is the shaft 1
4 and the shaft 14 is connected to the case 1
5 is attached. Inside the case 15, a vertical moving means for causing the suction head 12 to perform a vertical operation is incorporated.

The case 15 is mounted on a horizontal moving table 16. When the motor 17 is driven, the case 15 and the suction head 12 move horizontally between the conductive ball supply unit 2 and the work 4 along the moving table 16. Moving. The suction head 12 is connected to a vacuum suction system (not shown).
Then, the conductive ball 1 is vacuum-sucked, and the vacuum-sucked state is released. An optical system 20 is provided below the moving path of the suction head 12 between the conductive ball supply unit 2 and the positioning unit 5 of the work 4. Next, the optical system 20 will be described with reference to FIGS.

2 and 3, reference numeral 21 denotes a light irradiator. The light irradiator 21 is disposed on the side of the moving path of the suction head 12 and irradiates a beam light L parallel to the lower surface of the suction head 12 along the lower surface of the suction head 12. This beam light L is a laser beam.

Below the moving path of the suction head 12, a light emitting unit 22 also serving as a light input unit and a light source unit 23 are provided. The light source unit 23 includes a light source 24 that is a halogen lamp, a mirror 25 provided in front of the light source 24,
A light receiving section 26 provided below the mirror 25 is provided. The mirror 25 rotates about the pin 27.

The light emitting section 22 and the light source unit 23 are connected by an optical cable 28. The optical cable 28 contains many optical fibers 29. The optical fibers 29 led out from the distal end of the optical cable 28 are arranged in a line in a direction perpendicular to the moving direction of the suction head 12 (irradiation direction of the light beam L) inside the light emitting section 22. Therefore, when the mirror 25 is folded down as shown in FIG. 2, the light emitted from the light source 24 enters the optical cable 28 and is emitted upward from the upper end of the optical fiber 29 (arrows a and b in FIG. 2). reference). A light detection sensor 30 for detecting the light c leaked from the suction hole 13 is provided inside the suction head 12.

This conductive ball mounting device has the above-described configuration, and its operation will be described below. In FIG. 1, a suction head 12 moves up and down above a supply unit 2, and vacuum-adsorbs and picks up a conductive ball 1 in a suction hole 13 on its lower surface. Next, the suction head 12 is
, And passes over the light emitting unit 22 of the optical system 20 on the way. At this time, an inspection for the presence or absence of a pickup error is performed.

FIG. 2 shows the state of inspection for the presence or absence of this pick-up error. At this time, the mirror 25 is lying down, and when the light source 24 is turned on, the light is transmitted to the optical cable 2.
8 (arrow a), and is radiated upward from the upper end of the optical fiber 29 in the light emitting section 22 (arrow b). Here, when the suction hole 13 makes a pickup error and does not vacuum-suck the conductive ball 1, light enters the light detection sensor 30 through the suction hole 13 as shown by an arrow c. This indicates that there was a pick-up error. The determination as to whether or not there is a pickup error is performed by a CPU (not shown) of a computer connected to the light detection sensor 30 or the like. And if there is a pickup mistake,
The suction head 12 returns above the supply unit 2 and performs the pickup operation again.

When there is no pick-up error, the suction head 12 moves above the work 4. Then, the suction head 12 is lowered to land the conductive ball 1 vacuum-sucked on the suction hole 13 on a pad (not shown) of the work 4, and then releases the vacuum suction state and rises, thereby increasing the conductivity. The ball 1 is mounted on a pad of a work 4. Note that a flux is applied on the pad 4 in advance.

Next, the suction head 12 returns to a position above the supply unit 2. On the way, the suction head 12 passes above the optical system 20, and an inspection for the presence or absence of a mounting error is performed. FIG. 3 shows a state of inspection for presence / absence of a mounting error. At this time, the mirror 25 is in the inclined posture, and the light source 24 is turned off. Now, when the suction head 12 passes by the side of the light irradiator 21, the light beam L along the lower surface of the suction head 12 from the light irradiator 21.
Is irradiated. When the conductive ball 1 is attached to the suction hole 13, the light beam L is applied to the glossy conductive ball 1.
The light is strongly reflected downward by the spherical mirror surface (arrow d), and is incident on the optical fiber 29 of the light incident part 22 also serving as the light emitting part.
Then, the light is reflected by the mirror 25 through the optical cable 28 and enters the light receiving unit 26 (arrow e). Thus, it is found that the conductive ball 1 is attached to the lower surface of the suction head 12.

In this case, the point is that a part of the light beam L emitted from the light irradiator 21 may be reflected downward by the conductive ball 1 (that is, the light beam is transmitted by the conductive ball as in the conventional method). Since it is not necessary to completely block the light beam), the light beam L does not need to be reduced so much, and the light beam L may be slightly diffused. The conductive ball 1
The determination of presence / absence is also made by the CPU of the computer connected to the light receiving unit 26 or the like. In the example shown in FIG. 3, the conductive ball 1 adheres to the second suction hole 13 from the left side, but this is a mistake in mounting on the work 4 and remains on the lower surface of the suction head 12. is there.

As described above, according to the optical system 20, both a pickup error and a mounting error can be detected. Moreover,
An optical element formed by arranging the optical fibers 29 in a line is also used as the light emitting section 22 when a pickup error is detected and the light input section 22 when a mounting error is detected, and elements such as the optical fiber 29 and the mirror 25 are used for the pickup error. Since the optical system can be shared as the detecting unit and the mounting error detecting unit, the optical system can be simplified and the size and size can be reduced.

[0025]

According to the present invention, by utilizing the fact that the conductive ball is a glossy spherical mirror surface, the conductive ball is irradiated with light from the side of the suction head and reflected downward, thereby achieving a very simple structure. It can accurately inspect the presence or absence of mounting errors of the conductive ball. Especially, it is not necessary to completely block the light with the conductive ball. Can be inspected accurately.

[Brief description of the drawings]

FIG. 1 is a front view of a conductive ball mounting apparatus according to an embodiment of the present invention.

FIG. 2 is a side view of a suction head and an optical system of the conductive ball mounting apparatus according to one embodiment of the present invention;

FIG. 3 is a side view of a suction head and an optical system of the conductive ball mounting apparatus according to one embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductive ball 2 Conductive ball supply part 4 Work 5 Work positioning part 12 Suction head 13 Suction hole 16 Moving table 20 Optical system 21 Light irradiator 22 Light emitting part (light incident part) 26 Light receiving part

Claims (2)

[Claims] A conductive ball supply unit; a suction head having a plurality of conductive ball suction holes formed on a lower surface thereof; a work positioning unit; and a conductive ball supply unit and a work positioning unit. A moving table for moving between parts,
A light irradiator that irradiates light along the lower surface of the suction head from the side of the suction head in the movement path of the suction head, and a spherical mirror surface of a conductive ball that is below the suction head and is sucked into the suction hole. A conductive ball mounting device, comprising: a light receiving unit that receives light reflected downward. 2. A step of picking up a conductive ball provided in a supply section of a conductive ball by a suction head by vacuum suction to a plurality of suction holes on a lower surface thereof, and a work in which the suction head is positioned by a positioning section. Step of moving the conductive ball to the workpiece and mounting it on the workpiece, and after performing this mounting,
A step of irradiating light along the lower surface of the suction head from a light irradiator on the side of the suction head, and determining the presence or absence of a conductive ball based on whether or not a light receiving unit provided below the suction head receives reflected light. And a method for mounting a conductive ball.